MADISON - Gov. Tony Evers and Attorney General Josh Kaul joined a multistate lawsuit Wednesday challenging President Donald Trump's national emergency declaration to free up billions to pay for a U.S-Mexico border wall.

“The president’s declaration is reckless and unconstitutional,” Evers said in a statement. “This isn’t how a democracy is supposed to work."

The decision comes weeks after Evers and Kaul said they began exploring the idea of joining the legal challenge.

Evers said in a statement there "is simply not ample evidence to support the president’s contention that there exists a national security crisis at our southwestern border."

"The real crisis at our border is the separation of children from their families," he said, referring to a policy that has since been blocked by a judge of separating children from parents when families illegally cross the southern border.

Senate Majority Leader Scott Fitzgerald, a top Wisconsin Republican, disagrees with Evers' characterization of the situation at the U.S. border with Mexico.

In a tweet last month, Fitzgerald pushed back against Evers' decision to pull back troops from the border over concerns similar to those that prompted Evers' decision to join the federal lawsuit Wednesday.

"Drug smugglers and human traffickers cross our southern border every day — Wisconsin should be doing our part to keep our country secure," Fitzgerald said.

The lawsuit is brought by 19 other attorneys general and alleges the emergency declaration is unconstitutional.

"If Congress had chosen to divert those funds, that would simply be bad policy," Kaul said in a statement. "Here, however, the President issued an unfounded emergency declaration after Congress decided not to fund the border wall. That action is inconsistent with the constitutional mandate of separation of powers.”

The states allege in their lawsuit that Trump's emergency declaration exceeds the power of the president and unconstitutionally redirects federal money that Congress had set aside for other purposes. Trump made the declaration after lawmakers sent him a government funding bill that included $1.4 billion for the wall, far short of the $5.7 billion he initially requested.

White House officials said they believe they can unlock an additional $6.6 billion through the emergency declaration and other budget maneuvers. The White House believes the money would allow the administration to build at least 234 miles of the border wall, which was a central promise of Trump's 2016 campaign.

Wisconsin Republicans in December passed a number of laws limiting the power of Kaul and Evers, including barring both from withdrawing from federal lawsuits.